A

Adapting a novel for the cinema presents unique problems – it's not at all the straightforward process people assume, particularly if the novel is as complex and cerebral as Tinker, Tailor, Soldier, Spy. The screenwriters of this exceptionally fine and sombre new dramatisation of the novel (Peter Straughan and the late Bridget O'Connor) have perfectly reflected its labyrinthine world of bluff and counter-bluff, of suspicion and paranoia, of corruption and betrayal.

B

Betrayal is the novel's and the film's great theme – and perhaps the dark undercurrent beneath all of John Le Carré's work. Indeed one might claim that, among the few things we British are very good at – cricket, bespoke tailoring, dictionaries – is the spy novel. Possibly this is because we are also very good at betraying our country – our traitors are world-class and numerous, particularly since the second world war. The Cambridge spy ring still haunts the popular imagination.

C

"The Circus" is Le Carré's name for the fictional building that houses what, to all intents and purposes, is the headquarters of the British Secret Service and which overlooks Cambridge Circus (no coincidence) in the West End of London. The novel's plot, simply put, is that there is a traitor at the heart of the organisation – a "mole" in the very highest echelons of the service – and George Smiley, recently forcibly retired from the service, is re-recruited to find the man. There are five suspects – all identified by characters from the "Tinker, Tailor" jingle. Tinker, tailor, soldier, sailor, rich man, poor man, beggarman, thief. Smiley is himself a suspect – "beggarman" – and his search for the traitor is highly covert. He puts together his own team and, slowly but surely, they narrow the suspects down to one particular individual. It sounds simple but one of the delights of the novel (and the film) is its entwining complexity. You have to pay attention – only that way will its moments of bafflement be followed by dawning clarity.

D

David Cornwell (born 1931) is John le Carré's real name. As is well known by now, he was working for the Secret Intelligence Service, known as MI6, when he began to write fiction in the 1960s and was obliged therefore to choose a pseudonym. "Le Carré", so legend has it, was the name of a tiling firm whose advertisement he saw from the top of a bus as he was musing about what name to choose.

E

"The Expression of a nation's subconscious is its secret service." This adage from Tinker, Tailor may at first seem too pat and easy to survive any serious investigation. But, the more one considers it, the more acute it seems. Spying is as old as history itself, but secret intelligence services are fairly recent. Ours was founded in 1909. The CIA emerged from the second world war. When one thinks of other countries and their secret service manifestations – Russia and the KGB, Israel and Mossad, Pakistan and the ISI, even Uganda and Idi Amin's sinisterly bland State Research Bureau – the homily begins to appear particularly accurate. So how does that apply to Britain and MI5 and MI6? Le Carré himself once linked the character of the security services very tightly to that of the British establishment. All its complacencies and signal failures could be marked down to this identification.

F

Fiction is perhaps – paradoxically - the best way of telling the truth about spies and spying, particularly if you happen to have worked for the secret service and have signed the Official Secrets Act. The secret service is part of government, a department of the state, its members are civil servants, functionaries – however clandestine. Non-fiction accounts of the secret service are highly interesting but only for obsessives or former operatives, I would suggest, in the way that books about steam engines are fascinating only to train-spotters. The novel can glamorise that world (Ian Fleming, Tom Clancy), but the very best spy fiction (Le Carré, Len Deighton, Alan Furst) somehow gets to the essence of the profession – its "feel", its vital nature, its dark ambience – in the way that histories can't.

G

George Smiley is Le Carré's Mr Pickwick – in the sense that this fictional character seems to have leaped the bounds of the novels he has appeared in and has achieved a life of his own. Smiley is middle-aged, small, portly, bespectacled, a cuckold and a bibliophile – the very opposite of a James Bond or a Jason Bourne. His extra-literary life has been facilitated by two compelling portrayals of him in adaptations of Tinker, Tailor. The first was by Alec Guinness in the 1979 BBC television series and now, in the new film version, we have Gary Oldman in the new film version –, who commendably resists the temptation to channel Guinness and turns in a performance of mesmerising, still intensity. "Less is more" was never better exemplified.

H

"Handwriting", "Scalphunters", "Stock", "Fieldcraft" and "Lamplighters" are all examples of the jargon of spying that Le Carré has created and that have entered the lingua franca of espionage, almost as if they had always existed and he had merely appropriated them. Indeed one of the challenges of writing a spy novel today is somehow to escape the long shadow of Le Carré. Avoid his jargon, is one important piece of advice – make up your own.

I

Ideology – or rather competing ideologies – must be, so reason tells us, at the nexus of all cold war betrayals such as the one depicted in Tinker, Tailor. Whether the double agent is British (Philby, Burgess, Maclean, Blunt, Cairncross) or a Soviet defector, the motive for betrayal must be a profound dissension from the prevailing ideology (capitalism, communism) in the country he purportedly serves. Sometimes this is true. The other great British double agent of the 50s and 60s, George Blake, genuinely seemed to believe that a world governed by communism would be a better place. My own feeling is that ideology may explain the initial recruitment but that other forces come into play fairly soon thereafter. Certainly the traitor in Tinker, Tailor doesn't seem to be an ideologue. One of the abiding fascinations in studying the world of traitors and double agents is to try to arrive at a sense of motive – why would you want to betray your own country in the first place? How do you live that double life for years on end? Somehow, a belief in the fundamental rightness of the "communist way" doesn't seem a substantial or sustaining enough reason.

J

Joseph Conrad, John Buchan, Somerset Maugham, Graham Greene, Norman Mailer, John Banville, Ian McEwan – the list of serious novelists who have written a spy novel is long and distinguished. You could add Erskine Childers, Compton Mackenzie, Geoffrey Household, Joseph Hone – let alone those authors who would classify themselves almost exclusively as writers of spy fiction (Fleming, Le Carré, Deighton, Furst, Charles Cumming). There is something about the genre that is immensely alluring, particularly to the literary novelist – more appealing, I would argue, than the crime novel. At the core of the serious spy novel is the notion of duplicity and mendacity. All of us know those two abstract nouns intimately and we all employ them constantly in our daily lives, usually – and fortunately – to a minor and insignificant degree: all social life, for example, would grind to a halt without the "white lie", or the "pieux mensonge", as the French have it. The spy novel, while seeming to treat a rarified and, by definition, secret and unknown world, actually trades in concepts we all understand, instinctively and immediately. In some ways the world of the spy novel may be the best analogue of the human condition, writ large.

K

Karla is George Smiley's alter ego in the KGB – his great adversary, the spymaster supreme. There is a tremendous sequence of pages in the novel where Smiley and Karla come face to face in India, when Karla has been detained and Smiley is sent to interrogate him. Smiley seems happy to acknowledge Karla as the maestro. One of the problems of turning a long and intricate novel into a two-hour film is that a great deal has to be left out, and though this encounter is narrated in the film it is not seen. Somehow this contest between the two opposing intellects is at the centre of Tinker, Tailor – the quarry is not so much the traitor, the "mole", but Karla.

L

London, the city, figures almost as a character in Tinker, Tailor. So caught up are we in the unfolding intricacies of the plot that we forget how fine a writer of place Le Carré is. His topographical skills are as good as any, and parts of the city become vividly alive through his prose – Chelsea, Islington, Brixton and the environs of Liverpool Street station, for example.

M

Monologue is a somewhat outmoded literary device but one that le Carré uses a great deal and to great effect. Long narratives – flashbacks – are conveyed in pages of direct speech, uttered by this or that character. It's a device that transfers well to film – in some ways it works better as the monologue becomes voiceover, placed over scenes that we see in this new film filmed in Budapest and Istanbul, as well as London. For the screenwriter Le Carré's monologues are something of a gift.

N

Names are very important to Le Carré. He takes great care over the naming of his characters – no John Fosters or Sally Thompsons, Martin Smiths, or Jane Browns for him, however real and perfectly valid such names are. Instead, in Tinker, Tailor, we have Percy Alleline, Ricky Tarr, Connie Sachs, Roy Bland, Jim Prideaux, Peter Guillam and Toby Esterhase, among many others. A well-named character is instantly memorable and, thus identified, he or she immediately begins to live and breathe as a rounded person on the page.

O

Omniscience is another dated technique much favoured by Le Carré. He likes to be able to enter the minds of various characters from time to time and tell the reader what he or she is thinking. It's not much favoured today – subjectivity rules and the restricted point of view is pretty much the norm in fiction – but, for Le Carré, the advantage of the omniscient form means that the world of the novel is not seen exclusively by George Smiley – we get other angles, other interpretations. This is not a problem when it comes to adapting the novel for a film. In film there is basically one point of view – that of the camera lens – the objective stance is virtually immutable and all subjective variation succumbs to the power of photography. As viewers we are always on the outside looking in. In the novel there is a price to pay, however. If the author chooses the omniscient mode, then withholding vital information from the reader has to be a sort of sleight of hand. In the novel you can identify the traitor simply by analysing where the omniscience goes and where it doesn't. The author chooses not to tell us what one particular character is thinking – significant.

P

Philby. Harold Adrian Russell Philby – known to his friends as "Kim". Kim Philby is the great traitor in the post-war secret world – the superspy, 30 years a Soviet double agent. Le Carré has written eloquently and passionately about Philby in an introduction to a 1968 book, Philby: The Spy Who Betrayed a Generation. He described him as "an aggressive, upper-class enemy … of our blood and [who] hunted with our pack". The shockwaves of Philby's decades of betrayal still reverberate and, I believe, inform much of Le Carré's fiction. Philby – charming, stammering, a drinker, womaniser, Westminster School and Trinity, Cambridge, adored by his colleagues. The very fact that he was so effortlessly part of the complacent ruling elite was his best cover. No one could believe that an Englishman of his type could ever choose Russia over Britain. Kim, a traitor? Impossible, old chap. The double agent in Tinker, Tailor is a portrait of Philby (Le Carré uses Philby's Moscow code name, "Gerald" for his own traitor), even though the events of the novel are taking place 10 years after Philby's 1963 defection to the Soviet Union. Philby and the reasons for his highly successful and damaging betrayal of his country remain deeply mysterious and timelessly fascinating.

Q

Questions remain in literary circles about Le Carré (not that he cares a jot). Is he an excellent writer of genre fiction or a novelist of the first rank? The latter is the only answer. The fact that much of his output has to do with the world of espionage is irrelevant. No one would categorise Conrad as a writer of seafaring yarns just because many of his novels are to do with ships and sailors. Or should we reclassify John Updike's work because his world is largely confined to middle-class sexual imbroglios in New England? Novelists choose the arena they want to inhabit: it's their imagination and expertise that make them significant.

R

Russia is the great enemy in Le Carré's fictional world. It's a sign of time's relentless obliterating surge that the cold war, communism, the USSR, the Berlin wall and the threat of Russian hegemony seem historical curiosities. It's hard, today, to conjure them up as aspects of the "evil empire", as Ronald Reagan described the Soviet Union in 1983. It was a time and a world when bad guys and good guys could be easily identified, in theory. One of the great strengths of Le Carré's fiction is to show how blurred the moral line was between east and west.

S

The Secret Service has changed since Philby's day – or so we hope. We assume the old-boys'-club era has gone. The historian Hugh Trevor-Roper, who was recruited in the second world war, had this to say about the service and his colleagues as he found them at the time. The people he worked with possessed, he thought, "Very limited intelligence … By and large pretty stupid, some of them very stupid." Trevor-Roper knew Philby well and liked him enormously: he was profoundly traumatised by the revelation that he had been a Soviet double agent for decades.

T

Treason is at the centre of Le Carré's two masterworks of what we may call his middle period – Tinker, Tailor (1974) and A Perfect Spy (1986). Both, I feel, are inspired by the Philby case, and both seek to come up with an answer to the fundamental question – why betray, why choose to be a traitor? I'm not sure, finally, that Le Carré has the answer. In Tinker, Tailor he has the traitor say, "It's an aesthetic judgment as much as anything". The film script adds: "The west has become so ugly." I don't buy that (the Soviet Union is a model of grace and beauty?). There has to be something deeper.

U

Understanding, analysing and relishing the twists, turns and doublings-back of a Le Carré plot is an aesthetic pleasure, however, and one that the author deliberately foments. Complexity of plotting is a hugely underestimated literary art – it's not easy. Try to construct, over a three- or four-hundred page novel, a convoluted narrative that surprises and tests the reader and that ultimately joins all the dots, and see how you get on. One of the great achievements of the new film is that it manages to replicate the frisson of Le Carré's sinuously difficult and elliptical methodology. In the novel, the reveal of the traitor comes as a genuine surprise – so too in the film.

V

Vanity or venality? Paranoia or fatigue? What is it that undoes the double agent? It's hard to imagine the massive, near-intolerable pressures of living such a lie over years and decades, so what is the payback? The answer, I feel, is a form of glee. The successful double agent, exploiting the pretence, fooling everyone, enjoying the loyalty and credulity of peers and colleagues, can hardly stop laughing – inside.

W

"Witchcraft" is the name given in the novel to the double-bluff operation that the KGB ran, penetrating the highest level of the British secret service, leeching their secrets when the British thought they were being given gold dust by the Soviets. For the British, the great benefit of access to this "source" meant they could curry favour with their American counterparts. Nothing much has changed.

X

X-certificate is hardly a designation that could be applied to Le Carré's novels. The sex and violence count is very low and happens off stage, as it were – all is implication, not depiction. George Smiley and James Bond are without doubt the two most famous fictional spies in our spy literature but their worlds are miles apart.

Y

Yesterday's Men, one might say, looking at the glum world of Tinker, Tailor, with its tawdry portrait of 70s Britain (beautifully replicated in the film). Did we have those hairstyles, wear those clothes, enjoy that low-rent lifestyle? Yes, I'm afraid so – but that's irrelevant to the achievement of the novel and this new film. I believe Tinker, Tailor is Le Carré's chef d'oeuvre – its understanding of human nature is so acute and its masterful construction – its elaborate nuts and bolts – has never been bettered in his work. It's a superb novel by any standard and can sustain – a measure of its stature – many fulfilling re-readings.

Z

Zoltan Falosny, the structuralist and cultural critic, offers this explanation as to why people become traitors: there are basically three overriding reasons, he claims – money, blackmail and revenge. But I think there may be another – hate. Philby alluded obliquely to this when he was interviewed by a British newspaper after his defection to Moscow in 1963. He said he regarded himself as "wholly and irreversibly English and England as having been perhaps the most fertile patch of earth in the whole history of human ideas". Asked why he had betrayed this wonderful country, he said that he held a "humane contempt" for "certain temporary phenomena that prevented England from being herself". This is the disingenuous but crucial admission explaining Philby's treason. Moreover, the casual use of "England" and "English" is very revealing – the unreflecting language of the establishment. Here, I think, is the clue to the swagger and aplomb of Philby's sustained and astonishingly successful betrayal. He calls it "humane contempt" but I think "contempt" will do nicely. This has nothing really to do with Russia and communism – this is more an overriding desire to foul your own nest. Philby looked at the "English" world he'd been born into and found he had nothing but contempt for it. In such circumstances sometimes it is as easy to hate your country as it is to love it.